The present invention concerns a multiprotocol system for the exchange of information between a cordless local network using a first asynchronous type protocol and a fixed telephone network using a second synchronous type protocol, wherein the information comprises a digital voice a component coded according to the first protocol, wherein the system comprises a central unit and cordless terminals for transmitting the information to the central unit and wherein the central unit comprises converting means for converting the digital voice component from the first protocol to the second protocol.
From the PCT international patent application published with N. WO 96/09700 a communications system is known for interconnecting a cordless local network to a public network. Similar communications system are also known from the PCT international patent application published with N. WO 96/174884, from the European patent applications published with N. EP 615396 and N. EP 509548, and from U.S. Pat. No. 5,349,701.
The above communications systems provide solutions to different technical problems but relate to systems wherein the information, in particular the voice component, coded in the cordless local network according to the Adaptive Differential Pulse Code Modulation (ADPCM) speech coding standard, is exchanged with the public telephone network wherein the information is coded according to the Pulse Code Modulation (PCM) standard.
The above known systems require in the cordless local network to code the information, voice component or data (non voice component), solely according to the ADPCM speech coding standard; in fact such systems are not able to manage selectively a digital non voice component and a digital voice component through different channels.
From the PCT international patent application published with N. WO 94/05109 and from the U.S. Pat. No. 5,349,701 are also known apparatus for managing the information in the cordless local network, but also such apparatus suffer the constraints of the above systems; in particular such apparatus are able to exchange with the public telephone network information solely coded according to ADPCM speech coding standard.
Object of the present invention is to realise a system which permits the exchange of information between a cordless local network, using an asynchronous protocol, and a public network, using a synchronous protocol, by overcoming the constraints of the cited prior art and by employing a central unit possessing characteristics of simplicity, flexibility and inexpensiveness.
This object is achieved with the multiprotocol system according to the present invention characterized in that the information further comprises a digital non voice component formatted according to the first protocol (DECT) and in that the central unit comprises interface means for exchanging the digital non voice component with the fixed telephone network.